Process of making piston-rings



UNITED STATES PATENT OFFICE.

AXEL A. FOSSTON, 0F MINNEAPOLIS', MINNESOTA, ASSIGNOR TO SEAL-TITE PISTON RING' COMPANY, OF MINNEAPOLIS, MINNESOTA, A CORPORATION OF MINNESOTA.

PROCESS OF MAKING PISTON-RINGS.

Specification of Letters Patent.

Patented May 11, 1920.

Application filed July 24, 1918. Serial No. 246,475.

To all whom t may concern Be it known that I, AXEL A. FossroN, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Processes of Making Piston-Rings; and I do hereby declare the following tobe a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

h/ y invention provides an improved method of making piston rings. The improved method or process is especially adapted for making piston rings of the type disclosed and claimed in my prior Patent No. 1,147,228, of date, July 20, 1915. To the above ends, generally stated, the invention consists of the novel operations and steps of manipulation hereinafter described and dened in the claims.

The ring is illustrated in the accompanying drawings wherein like characters indicate like parts throughout the several views, and both the construction of the ring and the process by which it is produced, will be made clear by the following step by step operations which produce progressively the different stages of the ring illustrated in the drawings.

Referring to the drawings;

Figure 1 is a view in side elevation showing the blank ring from which the piston ring is produced;

Figs. 2 and 3 are face views illustrating dilerent steps in the process;

Fig. 4 is a fragmentary side elevation with some parts sectioned, showing the same stage of the ring as illustrated in Fig. 3;

Fig. 5 is a fragmentary side elevation illustrating another stage of the ring;

Fig. 6 is a side elevation showing the spring and blade of the ring seal;

Fig. 7 is a fragmentary side elevation illustrating still another stage in the. construction of the ring;

Fig. 8 is a face View and Fig. 9 is a side elevation, showing the ring just before it is machined to final form; and

Fig. 10 is a side elevationof the completed ring, some parts being broken away.

What may be treated as the first step of the process is to form a blank ring 11. This ring is primarily a concentric ring, that is, it has the same radial thickness and the same transverse thickness. This ring, if not formed accurately of exact proper transverse width, will first be ground or turned to exact width.

Treating the formation of the ring blank, itself, as the first step of the operation, the second, or next step is to cut or mill out at one place, an oblique transverse slot 12 which makes the ring a spring ring capable of contraction or expansion. The forming of the slot 12 may be done by a pair of saws, by a milling tool, or otherwise.

As a third step, an inwardly tapered rivet hole 13 is formed through one of the Spring ends of the ring. This hole will preferably be first bored straight and then reamed to tapered form.

As a fourth step of the operation, slots vor blade seats 14 are formed in the ends of the split ring; and this is preferably done by a milling tool 15 (see Fig. 5), which is applied from the inner side of the ring while the ring is compressed so that its ends abut. The milling tool thus used will form notches with curved bottoms that nearly cut through the outer surface of the ring blank.

Fitting the interior of the ring and adapted to lap the joint between the ends of th'e ring, is a grooved or segmental flat spring 16, and a thin blade or joint plate 17 is riveted or otherwise rigidly secured to one end of'` the said spring. This blade 17 has a projecting edge, but preferably, has the same curve as the milling tool 15, so that it will fit closely against the bottoms of the notches or seats 14 when the ring is compressed.

As the fifth step of the process, the spring 16, by' means of a rivet 18 applied in the tapered hole 13, is secured to one end of the split ring in such position that its blade 17 will fit in the notches or blade seats 14. When the spring and blade are thus applied, as shown in Fig. 7, the crown of the curved blade 17 will be about flush with the eX- terior of the blank or unfinished ring 11. This condition of the ring is also illustrated in Figs. 8 and 9.

As a so-called sixth, or last step of the process, the ring, with the sealing device applied as shown in Figs. 8 and 9, is compressed and the exterior thereof is then turned to eccentric form, as shown in Fig. 10. In this eccentric form, the end portions of the ring are turned off and made much thinner than the intermediate portion of the ring, and in thus turning oli the eX- terior of the ring, the outer portion of the blade 17 is cut off lush with the exterior of the ring and thus flattened so that it will have a considerably extended surface for engagement with the interior of the engine cylinder. The linished exterior of the ring will have such diameter that it will it the cylinder in which it is to be placed when nearly compressed to its limit and as the ring or the cylinder wears, the ring will expand. Also, the ring is given progressively increased flexibility toward its ends. Obviously, the ring may be turned eccentric in diilerent ways. Advisably, a plurality of the rings would be compressed and then clamped together onto a suitable eccentric mandrel, and the mandrel with the rings applied in the lathe in the well known way. The mandrel should iit the interior of the contracted rings so as to hold the blade in place during vthe turning operation, and thereby insure the proper cutting of the outer portion thereof.

lVhat l. claim is:

l. The process ot making piston rings which consists in turning' a blank ring, in cutting the saine transversely at one place to form an eXtensible split ring, in cutting blade seats in the split ends of the ring, in applying a joint blade in the seats thus formed, and thereafter, turning the ring to eccentric form, thereby reducing the thickness of the ends of the ring and cutting away or flattening the outer portion of the joint blade.

2. The process of making piston rings which consists in taking a complete blank ring', in cutting the same transverselyat one place to form a split spring ring, inv cutting notches to aii'ord blade seats in the split ends ofthe ring, in applying to one of the ends of the ring a spring having a joint blade litting the seats in the ends of the ring, and in compressing the ring and turning the same to eccentric form, thereby reducing the thickness of the ends of the ring, and cutting away or flattening the outer portion of said joint blade.

3. The process of making piston rings which consists in taking a complete blank ring, in obliquely cutting the same transversely Vto form a split spring ring, in boring a tapered hole in one of the ends of the ring, in compressing the ring and in cutting from the interior, curved notches affording blade seats in the ends of the ring, in applying by means of a rivet inserted in said tapered perforation7 a springl blade to that end of said ring, said spring having a flat curved joint blade itting'the seats in the ends of said ring7 and in turning oil the eX- terior of said ring while compressed to give the ring eccentric form with ends of reduced thickness and thereby, at the same vtime cutting away or' attening the outer portion of said blade.

In testimony whereof I afiix my signature in presence of two witnesses.

' AXEL FOS/STON. lVitnesses CLARA DEMAREST, F. D. MERCHANT. 

